Abstract : Test hardware was designed and fabricated which would permit biodynamic research to be conducted on both the AMRL IMPMODE and AMRL MONOMODE at their excitation limits. The existing Body Retraction Apparatus was modified to permit qualification and human testing. An instrumentation system including transducers, signal conditioners, and recorders was assembled to support the testing associated with the foregoing. Qualification testing was accomplished on all three devices with human testing conducted on the Body Retraction Apparatus. The program produced rugged test hardware for use in biodynamic experiments to investigate vibration exposure limits for human subjects and the inertial response of individual body segments during impact and vibration. In addition, a device and technique for investigating human tolerance to forcible retraction was developed and preliminary data collected. (Author)